1. Field of the Invention
The present invention relates to a control device for a vehicle provided with a power train having a driving source and a transmission, and more particularly to a control device for a vehicle capable of realizing such vehicular behavior that matches the driver's preference.
2. Description of the Background Art
Generally, an automatic transmission connected to an engine of a vehicle is automatically controlled by determining a gear ratio based on the amount of an accelerator operation by a driver and a vehicle speed. During normal traveling, the smaller the accelerator operation amount, and the higher the vehicle speed, the gear ratio is set to the higher speed side.
Concerning such control of an automatic transmission, Japanese Unexamined Patent Publication No. 09-501482 discloses a control device for an automatic transmission for the purpose of approximating the transmission behavior of an automatic transmission to a particular driver-type behavior. This control device for changing a gear ratio of an automatic transmission includes a detection unit detecting an input variable introduced from driver-vehicle system, a generation unit generating a dependent function of the input variable (fuzzy set) and a change unit changing a gear ratio. The input variable detection unit and the dependent function generation unit interact such that an output variable that determines a gear ratio is determined by a fuzzy creation rule. At least an input variable, a throttle valve position (absolute accelerator pedal position) and a displacement motion (the magnitude and direction of change over time of the accelerator pedal position) are combined with each other according to the fuzzy creation rule, and the amount representing the driver's output request that results from the combination forms an input variable for the basic rule group and the auxiliary rule group of the fuzzy creation rule.
With the use of the control device disclosed in Japanese Unexamined Patent Publication No. 09-501482, the driver's driving manner (comfort (comfortableness), economy (cost efficiency), sport (mobility), and the like) can be identified based on the driver's driving operation and reflected in transmission control. For example, the transmission diagram is changed according to such a driving manner, so that the automatic transmission is controlled to achieve harder upshift and easier downshift or controlled to achieve harder downshift and easier upshift. Here, some vehicles are provided with a traveling mode switch for detecting such a driving manner (to manually switch among comfort, sport, economy, and the like) to allow the driver to manually select the driving manner.
However, when learning control is executed equally irrespective of the selected traveling mode, as in the control device disclosed in Japanese Unexamined Patent Publication No. 09-501482, the driver's request for the driving manner may not be reflected properly. As a result, when the vehicle is traveling, the driver's preference is not reflected so that the driver may feel uncomfortable with the unexpected or unpredicted vehicular behavior.